Field of the Invention
The present invention relates to an engine control device, and more particularly to an engine control device for controlling engine torque based on an accelerator actuated amount or the like.
Description of Related Art
When a vehicle is to be accelerated (especially when a vehicle movement is changed from a deceleration mode to an acceleration mode), vibration may occur in the vehicle if engine torque is increased abruptly, so that a control has conventionally been adopted to have the engine torque increased slowly for suppressing such possible vibration. However, if the engine torque is increased slowly, vibration at the time of acceleration may be suppressed but there is a negative effect that acceleration performance comes down. A technique for solving such a problem is disclosed in Patent Document 1 (Japanese Laid-Open Patent Publication 2005-155412 A), for example.
The Patent Document 1 discloses a technique to control engine torque so as to achieve a good balance between suppression of longitudinal vibration of a vehicle body caused by torsional vibration of a drive shaft, and acceleration performance. Specifically, in this technique, when rate of depressing an accelerator pedal is high, a control is performed which permits a longitudinal vibration of the vehicle for a certain degree to increase engine torque abruptly, and when rate of depressing the accelerator pedal is low, another control is performed in which engine torque is increased moderately in order to suppress the longitudinal vibration of the vehicle.